1. Field of the Invention
The present invention relates to processors of sheets of photosensitive material.
2. Description of the Prior Art
Automatic photosensitive film and paper processors transport sheets or webs of photosensitive film or paper through a sequence of processor tanks in which the photosensitive material is developed, fixed and washed, and then transports the material through a dryer.
In the case of graphic arts film and paper processors, the photosensitive film or paper is typically in the form of strips or sheets. To perform dot etching, it is necessary to rewash and redry sheets of previously processed material in a graphic arts processor. To accommodate rewashing, graphic arts processors such as the 24ML processor manufactured by Pako Corporation, the assignee of the present application, provide a built-in rewash slot. In the 24ML processor, the rewash slot is located at the top of the processor, on the light room side (rather than the dark room side) of the processor. When a sheet of material is fed into the rewash slot, it is directed downward into the wash tank, and is then transported through the dryer. The 24ML processor includes a rewash switch which is turned on when an operator desires to feed a sheet into the rewash slot, and a rewash wait light. After rewash switch has been turned on, the rewash wait light remains on until the last sheet being fed through the processor drops into the catch basket at the exit of the processor.
Processors of photosensitive material commonly include a sensor or sensors at the inlet end of the processor. Signals from the film sensor are used to activate the transport system of the processor, and in some cases to operate other systems as well. For example, U.S. Pat. No. 4,057,817 by Korb et al shows an x-ray film processor in which the presence of film at the infeed tray of the processor causes a timer to be activated. This timer operates the processor control to switch the processor from a normal standby mode to a processing mode for a preset timing interval. This minimizes the water and energy consumption of the processor.
U.S. Pat. No. 3,852,793 by McClintock shows a photographic film processor having a film sensing switch at the inlet end of the processor which activates and controls flow of water into the processor. When the trailing edge of a piece of film passes the switch, a timer begins a timing cycle. If no further film enters the processor before the end of the timing cycle, the water to the processor is turned off. If a subsequent film enters the processor during the timing cycle, the timer is reset. Water to the processor is turned off after a predetermined period of time has elapsed after the trailing edge of the last piece of film has entered the processor.